Presently, there are about 2 million large water meters, meters having a 3 inch or greater inner diameter, in the United States. Generally, large water meters are compound, turbine or fire service meters serving commercial or large residential installations. A compound meter is designed to provide accurate reads through both low and high water flows. These meters are used, for example, in apartment complexes and schools, which alternate between periods of high and low water usage. Turbine meters are designed for high water usage, for example at industrial facilities such as beer breweries. Three manufacturers, Schlumberger, Hersey and Sensus, produce nearly 90% of the large water meters in the United States. A meter's size (3", 6", 10", etc. for large water meters), type (e.g. compound, turbine or fire) and manufacturer (e.g. Schlumberger, Hersey or Sensus) describe the meter model.
Although large water meters represent only approximately 1% to 2% of the total water meter population in the United States, they generate 50% to 60% of municipal water revenues. Unfortunately, however, these meters tend to suffer reduced accuracy over time. In particular, they tend to record less water than was actually used, thereby creating a revenue loss to the municipality. For example, assume a large water meter for a large industrial facility is tested against a calibrated test meter and is found to be 90% accurate. Assume also that the municipality's billing records indicate that the meter was billed $50,000 in the previous year. By dividing $50,000 by 90%, the bill to the industrial facility should have been $55,555.00. Thus, the municipality lost $5,555.00 for a single water meter in a single year.
To avoid excessive meter revenue loss, some municipalities test their meters against calibrated test meters. However, a two man field crew can test only about 4 to 5 large meters per day. In a typical city having 250 to 500 large meters, this procedure is often prohibitively inefficient and expensive. Accordingly, many municipalities simply replace large water meters at a predetermined age (time following installation), for example 15 or 20 years. Thus, the municipality accepts revenue loss rather than undertaking the burden of determining when the loss of water meter accuracy justifies replacement.